Long-wave elastic anisotropy produced by horizontal layering

摘要: A horizontally layered inhomogeneous medium, isotropic or transversely isotropic, is considered, whose properties are constant nearly so when averaged over some vertical height l′. For waves longer than l′ the medium shown to behave like a homogeneous, density average and elastic coefficients algebraic combinations of averages original medium. The homogeneous said be ‘long-wave equivalent’ Conditions on five derived which necessary sufficient for Further conditions also consisting only two different materials. Except in singular cases, if latter two-layered exists at all, its proportions uniquely determined by observed variations crustal P-wave velocity with depth, obtained from well logs, large enough explain anisotropies as due layering material.